This section provides background information related to the present disclosure which is not necessarily prior art.
FIG. 1 illustrates an exemplary embodiment of cervical vertebra fixation devices disclosed in KR Patent Official Gazette No. 10-0974498, in which the cervical vertebra fixation device 100 has a body 110 in plate form. A plurality of openings 120; 121, 123, 125 is formed in the body 110, and screws 130 are inserted and guided in these openings 120; 121, 123, 125, respectively, to be fixed to a bone. A resilient cover 150 is used to prevent any escape of the screws 130 inserted. Among other components not yet described, 151 denotes escape-preventing protrusions 151 formed in the resilient cover 150, and 160 denotes windows 160 through which a person can check an insert arranged between adjacent cervical vertebrae. Further, the screw has a body 131, an outer peripheral surface 131a and a thread 131b. 111 denotes the top face of the body of the cervical vertebra fixation device.